Cylinder lock



A. A. SAARENTO CYLINDER LOCK Filed Dec. 9, 1953 INVENTOR. u//s Adr/Qn Saa/enzo A 7' TORNEY.

April 29, 1958 Uff Y# l l w United States Patent 'i CYLINDER LUCK Aulis Adrian Saarento, Jyvaskyla, Finland Application December 9, 1953, Serial No. 397,158

Claims. (Cl. 70-364) The present invention relates to cylinder locks.

Cylinder locks, as at present commonly used, comprise a casing and a key actuated cylinder fitted therewithin, said cylinder having positioned therein a plurality of plate tumblers arranged transversely of the'cylinder axis and adapted to be directly driven by a proper key into locked or unlocked position. The present day cylinder locks have, however, numerous disadvantages both from the manufacturing and operation standpoint and are high in cost.

It is therefore an object of this invention to provide an improved cylinder lock comprising a casing and cylinder fitted therewithin, said cylinder having positioned therein a plurality of tumblers adapted to be moved into and ont of engagement with the casing for locking and unlocking the lock, respectively.

Another object of the invention is to provide an improved cylinder lock which has all the advantages of the present cylinder locks, but is simpler in construction,

can he manufactured a-t much lower cost and is for all practical purposes substantialy pick proof.

A. still further object of the invention is to provide an improved cylinder lock capable of being set up to a great number of combinations by positioning each tumbler alternatively in one of two positions within the cylinder.

These and other objects will be apparent from the following description taken in connection with the accompanying drawing wherein:

Fig. l is a longitudinal section of a lock embodying the invention in locked position and Fig. 2 is a cross section taken along line II-II of Fig. l.

Fig. 3 is a view similar to Fig. l but showing the lock in release position.

Fig. 4 is a cross section taken along line IV-lV of Fig. 3.

Fig. 5 is a section taken along line V--V of Fig. l and Figs. 6 and 7 show a tumbler in top plan view and side view, respectively.

ln the drawing 1 denotes the casing which is shown in part only and can he of any exterior contour, and may form part of a device with Which the lock is used. The casing is provided with a cylindrical bore having two diametrically opposite, longitudinal recesses 7. Within the casing is fitted the cylinder 2 having positioned therein the plate tumblers 3 all of which are provided with an opening 12 of identical shape dimensions, as illustrated in Fig. 6 and dened by lines parallel by twos. The middle part of the tumblers is somewhat thinner than the ends thereof, as shown in Fig. 7. At the front end of the tumblers is provided a cover disc 5 having an opening corresponding to the maximum cross section of the key bit 4- and provided with a stop 8 arranged yto move in a groove 9 in the casing wall. The opening in the cover disc has a notch which registers with a slot in the key proper to insure insertion of the key thereinto in the 2,832,221 l Patented Apr. 29, 1958 correct way. A spring 6 is provided to press the tumblers together. The proper key for the present lock has its bit provided with a plurality of spaced, diametrically opposite notches or teeth of different lengths to accord with the different lengths of the surfaces 10 in the tumbler opening, the en-d faces of the notches or teeth being bevelled. The object in providing bevelled edges 11 at the key bit end is to facilitate, upon insertion of the key into the lock, the replacement of the tumblers into correct position should fraudulous or accidental motion have displaced the same.

The length of the lugs on each of the tumblers and the height of the corresponding notches or teeth in the key bit are so adjusted relative each other that turning of the key into locked position always projects one of the two lugs into one of the two recesses 7 while the other is released from its respective recess; the total diameter of the tumblers at the lugs tops is such that with the tumblers released from the locking position the tumblers will rotate freely within the casing, while the cylinder follows suit.

The lock functions in the following manner:

In locked position the diametrically outwardly projecting locking lugs of the tumblers reside in their respective recesses 7 in the casing 1. When the key is turned clockwise the tumblers 3 are retracted, by registration of the notches or teeth in the key bit with the operative surfaces of the openings 12 in the tumblers, until the locking lugs are brought into alignment with the periphery of the cylinder 2. When the lugs are in alignment with the cylinder, the same can be rotated relative the casing until the stop 8 in the cover disc 5' hits the one end of the groove 9 in the casing, during which rotational movement the lock is released by virtue of the rotative movement of the cylinder being relayed to the lock bolt by suitable members not shown in the drawing. Upon locking the lock the key is turned in counter clockwise direction, whereby the cylinder will rst rotate relative the casing until the same stops as a result of the action of the hereinabove mentioned members, whereby the lock* ing lugs will be moved right in front of the recesses 7. Further turning of the key causes the tumblers to be projected so the lugs thereof enter into the recesses 7, whereby the key is released also.

Because `the casing-is arranged to limit the rotary motion of the cover `disc the cylinder cannot be rotated, by means of the cover disc, into such a position wherein the lug edges would hit the walls of the recesses17, and thereby render picking of the lock possible.

Picking is also render impossible by the fact that friction between the tumblers makes it impossible to actuate a tumbler without concurrently actuating one or two others. in like manner it is impossible to release the j lock with a key wherein even just one of the notches or teeth is defective.

By suitably selecting the number of tumblers and variations in key teething it is possible to set up a great number of combination possibilities.

It is to be understood that the invention is not limited to the embodiment described as an example, for various constructional details can be modified within the scope of the appended claims.

What l claim is:

l. Cylinder lock comprising a casing, two diametrically opposite internal grooves in said casing, a cylinder Within said casing, said cylinder being adapted to rotate Within said casing, a plurality of tumblers positioned within said cylinder adapted to normally engage one of said grooves in said casing, said tumblers having central key openings uniform in size and shape and wholly defined by opposed pairs of parallel lines to be engaged by a key inserted into said key openings, whereby rotation of the key directly disengages said tumblers from said grooves and centers the same within said cylinder for permitting rotation of said cylinder Within said casing in one direction to unlock the lock, and rotation of the key in the other direction directly engages said tumblers with said grooves to lock the lock.

2. Cylinder lock according to claim 1 including a cover disc positioned outside of said cylinder adapted to dene said tumblers outwardly and having the rotary motion thereof limited by a stopping means arranged thereon and adapted to move in a correspondingly shaped groove in the lock casing.

3. Cylinder lock according to claim 1, wherein the middle part of said tumblers is thinner than the ends thereof.

4. A cylinder lock comprising a casing having a pair of oppositely disposed grooves therein, a cylinder rotatably disposed Within said casing, a plurality of tumblers Within said cylinder, and means for holding said tumblers in frictional engagement one with the others, each of said tumblers being adapted to be engaged with and disengaged from said grooves and having uniform key-receiving central openings defined by pairs of parallel side walls, one pair of said parallel side walls being positioned tto be engaged by a keyon rotation thereof in one direction and another pair of said parallel side walls being positioned to be engaged by said key on rotation thereof in the other direction, whereby rotation of said key in said central openings in one direction directly engages the key bittings of said key with one pair of said parallel side walls and disengages said tumblers from said grooves and rotation in the other direction directly engages said key bittings with another pair of said parallel side walls and engages said tumblers with said grooves.

5. A cylinder lock according to claim 4 wherein said central openings are in the shape of irregular polygons with the portions on each side of a center line being similarly shaped.

References Cited in the ile of this patent UNITED STATES PATENTS 327,715 Paull et al. Oct. 6, 1885 730,831 Loch June 9,1903 1,218,065 Diesel Mar. 6, 1917 1,702,430 Fremon Feb. 19, 1929 1,784,444 Homolle Dec. 9, 1930 2,151,245 Swillens 1 Mar. 21, 1939 2,647,391 Uher Aug. 4, 1953 FOREIGN PATENTS 134,217 Germany Sept. 18, 1902 708,993 Germany Aug. 2, 1941 

